Fusible link



May 15, 1923.

J. DAWSON FUSIBLE LINK Filed March 5, 1921 2 sheets-Sheet 1 INVENTOR dazzhfiawsorg By M,

ATTORNEYS J. DAWSON May 15, 1923.

FUSIBLE LINK Sheets-Sheet 2 Filed March 5 1921 INVENTOR Jbszbh Dawson,

' BY WW/W W/ TNESS A TTORNEYS Patented May 15, 1923.

JOSIAH DAWSON, OF PHILADELPHIA, PENNSYLVANIA.

FUSIBLE LINK.

Application filed March 5, 1921. Serial No. 449,755.

T 0 all whom it may concern:

Be it known that I, JOSIAH DAWSON, a citizen of the United States, and a resident of the city of Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented certain new and useful Improvements in Fusible Links, of which the following is a specification, reference being had to the accompanying drawing.

My invention relates to fusible links for automatic sprinkler heads, fire doors and other apparatus designed to function upon the heat actuated release of a link or other device normally under tension, among its principal obj ects being to provide a link of extremely simple construction which may be manufactured at a low cost and embodying'means other than the fusible metal or solder by which the members of the link are normally held in assembled relation for resisting the longitudinal strain or tension to which the link is normally subjected when in use. Further objects of the invention are to provide a link embodying a key or strain resisting member of the character aforesaid in which the member is so arranged that when the link is assembled and soldered together a portion of the member is readily visible so that it may be readily observed whether or not the member has been properly assembled in the link and is, in fact, in position therein.

Still further objects of my invention are to provide a link for the purposes aforesaid comprising members adapted to beunited by fusible metal and embodying means effective to bring about the rapid and positive separation of the members upon the fusing of the metal.

My invention further includes all of the other objects and novel features of construction and arrangement hereinafter more definitely specified and described.

In the accompanying drawings 1 have illustrated certain forms of the'invention, Fig. 1 being a front elevation of a preferred form thereof with the parts in assembled position and united by solder or other suitable'fusible material; Fig. 2 is a side elevation of the assembled link shown in Fig.

1 in operative position on the arms of a sprinkler head; Fig. 3 isa side-elevation of the link and sprinkler head arms showing tion; Fig. 5 is a composite view showing posite view similar to Fig. 5 showing a' slightly modified form of the invention;

Figs. 8 and 9 are views thereof respectively similar to Figs". 2 and 4, and Fig. 10 is a composite view similar to Figs-5 and 7 but showing a still further slightly modified form of the invention. Likenumerals are used to designate corresponding parts in the several figures.

The form of the invention shown in Figs.

1 to 6 inclusivecomprises a pair of plates.

each plate being located nearer one end thereof than the other, and preferably so that the distance from such. point to one end of the plate is' substantially twice that to the other end. From this point of greatest width the adjacent lateral edges of the plate respectively converge in opposite directions toward the ends, sothat the plate presents a generally kite-shaped appearance, the angle between the converging edges adjacent one end being considerably greater than at the other. Either simultaneously with the blanking operation just described or in a separate operation, one of the plates as, for example, plate 1, is provided with an aperture 3 adjacent its obtuse end and the other plate with :1. preferably similar aperture 4 adjacent its narrow end, and the end of each plate opposite to that adjacent the apertureis respectively cut off in a more or less generally transverse direction, as at ,6 and 6, so that when the plates are turned end for end and disposed one upon the other with,

their respective faces X and Y adjacent as in Fig. 1, the edge 5 will lie adjacent the aperture dand the edge 6 adjacent the aper ture'3 leavingboth apertures free "for the passage of the sprinkler headarms. I

Each plate in this form of the invention may be provided with a pair of preferably parallel laterally spaced slots positloned; sub

stantially equidistant fromthe ends of the plate, the slots in plate 1. being designated as 10 and those in plate 2 as 12. The slots in each plate are located on opposite sides of its center line and the metal lying between the slots is struck outwardly to provide a curved portion 14: extending beyond the outer surface of the plate and, forming a substantially semi-cylindrical depression or cavity 15 lying between theslots adjacent the inner surface of the plate, these depressions and the adjacent slots being so disposed in the respective plates that when thelattcr are assembled, the slots in each plate-will align with those in the other, the two semi-cylindrical depressions thus forming ,a-substantially cylindrical opening ex tending transversely of the plates and bounded by the struck-out portions 14:.

Within this opening: positioned what for convenience may be termed the key member which is best shown in Fig. 6 and comprises a spool having a cylindrical body 20 and outwardly dir eted preferably integral flanges 21 of similar diameter positioned at the ends thereof. The diameter of the body 20 is preferably substantially thatof the cylindrical opening formed betwecnthe struck-out portions oi the respective plates, while the diameter of the flanges 2-1 is preferably very slightly less than the length of the slots 10 and 12. Moreover the total over-all length of the key member is preferably very slightly less than the disence between the outer edgesof each pair of slots and the length of the body portion 20 slightly greater than the width of the struck-out portion 14 so that when the key member is positioned between the plates and. centrally disposed with respect thereto; there preferably is a very slight clearance 22 between the outer faces of the flanges 21 and the outer sides of the slots and a similar clearance 23 between the inner sides of the slots and the inner faces of the flan ges.

lVhen assembled. the several. elements composing the linkare united in the ordinary manner by solder or other fusible metal 25 which is distributed between the adjacent faces of the plates and also ordinarily Flows out through theclearances 22 and 23 and collects on the surface of the plates adjacent theends of the key member as indicated at 27, 28. It will be evident that with the parts assembled in the manner described, portions of the flanges of the key member will at all times be visible above the small amount of fusible metal '27. 28 which ordinarily collects on the outside o? the plates during-the soldering operation. so that it may be readily ascertained by inspection at time whether or not the key memherbeen properly 1 positioned between plates i the assembling process; I-Tenee the danger of assembling one sprinkler head for operative use a. link from which the key member has been omitted through carelessness or oversight during assembly is avoided, as a very cursory inspect-ion will readily reveal the presence or absence of the key member.

The link issnow in condition to be placed in operative position, for example upon the arms A, B of a. sprinkler head with the ends of the arms projecting through the apertures 3 and 4, in which pos tion the normal tendency oi the arms to move outwardly in opposite directions, due to the construction of the head as \VllLbQ readily understood by those familiar with the art, subjects the link to longitudinaltension or strain which, in the absence of the key member, might cause the solder to give way and permit either total separation of the plates or else a slight relative longitudinal leakage of the the fusingpt the fusible metalwhich unitesthe plates. the strain eserte'd on themby the sprinkler head arms immediately causes a relative longitudinalimoveinentof the plates in opposite directions which is effective to cause the inner ec ges of the lower ends ol? the slots 10 to ride up on the peripheries ot the flanges 21 0f the key memher and the innereclgesot theiuppenends of the slots 12 to similarlyvride' up at a substantial y diametrically opposite point on the flanges as-shown in Figs. (land 4, and as the relative longitu'dinal'displacement oi the plates progresses, the said edges'of' the respective slots continueto ride up upon thejedges o'li theflangeswhereby the plates are rapidly and positively forced apart in a direction substantially at right angles to their planeol nelat-ive longitudinallmovement. the llangesolin client, formingeams operative to force the plates apartr By reason of the rela cly l diameter of the rian s the plates are thus positively moved apart tor a distance suflicienl'ly great to prevent the Fused solder, wh ch is immediately chilled by the rushv of water from the: head which follows the initial move;-. ment of thearins, from reuniting the plates and thereby preventing" the proper functioning of thefihead.by-checkingthe'fiow therefrom before it reaches it maximum intensity, and as the ends'otthe slots when the lmk is assembled lie'either incontact with theflanges ;orvery. slightly spaced lot v therefrom, the outward movement of the slightly modified form of the invention which is" substantially similar in all respects to the form of the invention hitherto described save that the metalin one of the plates, for example plate 1, is struck outwardly adjacent the outer edges of the slots 10 thus providing a curved, preferably substantially send-cylindrical portion 30 adjacent the outer edge of each slot which bounds, a corresponding depression or cavity 31 in the inner face of the plate. In order that, when the plates are assembled on each other, their adjacent surfaces may be brought together, the other plate adjacent the outer edge of each of the slots 12 is cut out as at 32 to provide apertures through which the struck-out portions 30 may extend, as best shown in Fig. 8. When the link is assembled and the several parts united by the fusible material, a quantity of the latter may be deposited in each of the depressions 31 adjacent the ends of the flanges 21 of the keymember, thus forming a relatively considerable massof fusible material adjacent the ends thereof which tends to very firmly retain the key member in position. The operation of this form of the in vention is substantially similar in all respects to that of the form previously described, and will be readily comprehended by reference to Figs. 8 and 9.

In Fig. 10 I have shown a still further slightly modified form in which but a single slot 35 is provided in each plate, the metal adjacent either side of the slot being struck outwardly as at 36 to provide substantially semicylindrical cavities or depressions in the faces X and Y of the plates, .so that when the latter are brought together a. substantially cylindrical cavity will be formed adjacent each side of the slot adapted to receive the cylindrical portions 39 of the key member. The latter is provided between the portions 39 with an outwardly directed flange 40 which enters the slots 35 in a manner similar to that in which the flanges 21 enter the slots 10 and 12, and is similarly effective to force the plates apart by a sort of camming action upon the fusing of the fusible metal which normally unites the various elements in assembled position.

While I have herein described and illustrated in the accompanying drawing certain embodiments of my invention with considerable particularity and have shown the same in connection with the arms of a sprinkler head, I do not thereby desire or intend to limit myself to any precise details of construction and arrangement of the several parts norto the use of plates of any particular contour, as the former may be varied in minor particularsas desired,plates' of other contours than those illustrated may i be employed and the link used in connection I with fire doors and other devices without departing from the spirit and scope of the invention as defined in the appended claims. Having thus described my invention I claim and desire to protect by Letters Patent of the United States i j 1. A fusible link comprising a pair of plates united by fusible material, each plate". v

having a slot and a cylindrical key member having an outwardly directed peripheral flange disposed between the plates with said flange projecting into said slots.

2. A fusible link comprising a pair of plates united by fusible material, each plate having a pair of slots, and a cylindrical key member disposed between the plates and having peripheral flanges projecting into said slots. i i

3. A fusible link comprising a pair of oppositely disposed plates united by fusible material, each plate having a slot' and an outwardly struck portion adjacent thereto,

said portion bounding a depression formed in the inner face of the plate, and'a cylindrical key member having peripheral flanges and positioned between the plates partially in said slots sions.

4. A fusible linkcomprising'a pairof oppositely "disposed platesunited by fusible material, each platehaving a, slot and a depression adjacent thereto inits inner face, and a cylindrical key member having portions of different diameters positioned between the plates partially within the slots and partially within th depressions.

5. A fusible link comprising a pair of plates united by fusible material, each plate having a slot on each side of its median line and a key member positioned between the plates and having flanges entering said slots when said plates are. assembled and adapted under operative conditions by engagement with the ends of said slots to cam said plates apart when said fusible material is fused.

and partially insaid 'depres-,

outwardly directed 6. A fusible link comprising a pair of disposed on opposite sides'of its median'line, a depression formed in each plate between the slots therein and a key. member having a portion adapted to enter said ClGPTQSSlOD and other portions adapted to enter saidslots whcnthe plates are assembled to form thelink. y

8. A fusible link comprising a pair of plates each having a pair of parallel slots disposed on the opposite sides of its median line, and a key. member having a body portion adapted to extend transversely between thetslots and outwardly directed cylindrical flanges adapted to enter the slots when the plates are assembled to form the link.

9. A- sprinkler .head' link comprising a pair of plates adapted to be united by fusible material each plate having a pair of parallel slots disposed on the opposite sides of its median line, the material from which the plate is formed beingstruck eutwardly between the slots. to form a semi-cylindrical depression-in the inner face of the plate, and alkey member comprising. a cylindrical bodyv portion and an outwardly directed flange adjacent each end thereof, said body portion beingv adapted to rest in said semicylindrical depression and said flanges to enter, said slots and extend beyond the outer faces of the plates when the plates are assembled to form the linln I 10. A sprinkler head link comprising ,a pair of plates adapted to be united by fusible-material, each plate'having a pair of slots disposed. on opposite sides of its median line, the. material from which, the plate is formed being struck outwardly between the slots to provide a substantially semiecyli'ndrical depression in the inner'face'ot' the plate extending transversely of the slots, and a key member having a cylindrical body portion adapted to rest in the cylindrical aperture formed between the plates when the latter are assembled to formfthe link and a pairof outwardly directed flanges of greater diameter than said body. portion adapted to enter said slots and to extend beyond the outer faces of the plates where.- by said flanges are visible above the outer surfaces of the plates when the link is assembled, the inner edges of theends of the slots being operative to ride on said flanges when the-plates of the link are moved longitudinally in opposite directions.

11. A fusible link. comprisinga pair of con'iplementary plates adapted to be united by fusible material, each plate having a pair. of parallelslots disposed on opposite sides.

of its median-lineand a depression formed between the slots, and. a key member adapted to rest in said depression and havingoutwardly directed flanges adapted to enter said slots when the.link is assembled, the inner edges of the-ends of the slots being operative to ride on the edges of the flanges to force said plates apart simultaneously with a relative longitudinal movementmof the plates.

In witness whereof, I have hereunto set my hand-this third day of Manch, A. D; I i

JOSIAH DAWSON. 

